Genetic and environmental variation in architecture and yield components in determinate white lupin (Lupinus albus L.)

Summary Determinate architecture is of great interest for lupin production in Europe but the extent of genetic and environmental variation in the structure and yield of determinate lupins must be evaluated. Forty-three genotypes of determinate autumn-sown white lupin were studied in four environments in France in 1991/92 and 1992/93. Wide variation was observed for phenological (dates of mainstem and branch flowering, date of end of flowering and date of maturity), morphological (numbers of branch orders, branches and leaves) and seed characters (seed yield, mean seed weight, number of seeds/m²). Both genetic and environmental effects contributed to the observed variation. Heritabilities were high for all characters, and the interaction between genotype and location effects was low. There were significant positive correlations of flowering dates with vegetative plant development including the number of branches, number of leaves and number of branch orders. Seed yield and phenological and archtectural characters were significantly correlated. Distribution of yield on the vegetative orders showed important variations according the genotype, and the variations were related to variation for the architecture. There are possibilities for yield improvement using morphological characters in determinate autumn-sown lupin.     

Biplot analysis of trait relations of white lupin in Spain

A 2-year study of autumn-sown white lupin (Lupinus albus L.) was conducted under rainfed Mediterranean conditions in southern Spain. 108 landraces were evaluated for yield and major phonological and plant structural characteristics. Path coefficient and Genotype-Trait (GT) biplot analysis were used. Applying both types of analyses to the multiple trait data revealed that GT biplot graphically displayed the interrelationships among traits and facilitated visual comparison of accessions and selection. Wide variation was observed for trait phenology (dates of flowering and maturity), plant structure (plant and first order inflorescence height) and yield characters (first order branches, first order inflorescence and total yield). It was found that the accessions with the highest yields were the tallest and the latest to flower, both on the mainstem and on the lowest first order branch, and also were the latest to mature. GT biplots also had suggested as the accessions have been displayed according to their origins. The results showed that foreign germplasm may be an important material for improving some yield components such as number of pods and seeds per plant of locally adapted lupins in Spain. This revised version was published online in July 2006 with corrections to the Cover Date.     

Genetic variation for pod wall proportion in Lupinus albus

The proportion of pod walls is considered as a potential selection criterion for seed yield in white lupin. It has a negative and highly significant phenotypic relationship with the seed yield and the genetic correlation between both traits is negative and high. The present study over 2 years (1996 and 1998) evaluated the genetic variation of proportion of pod walls in a set of 325 spring‐sown white lupin accessions originating from 17 different countries. Wide ranges of variation for this trait and other pod components were observed. This variation has a geographical distribution. Egyptian ecotypes had the lowest proportions of pod walls while the Greek and Italian ecotypes had the highest. The between‐country range of variation for the proportion of pod walls, was lower than the within‐country range (0.25‐0.31 and 0.21‐0.36, respectively) and the within‐country variance accounted for 51% of the total genetic variation. The broad‐sense heritabilities of pod wall proportion and proportion of pod walls for one full locule were moderate (0.44 and 0.57, respectively), which indicates that the proportion of pod walls can be used in breeding.     

Partial resistance to a Fusarium root disease in Egyptian white lupin landraces

A Fusarium sp. root pathogen of lupin is the causal agent of the most important disease that affects the cultivation of white lupin (Lupinus albus L.) in Egypt. The aim of our research was to investigate whether host resistance to Fusariumroot disease was available in Egyptian landraces ofLupinus albus. Five Fusarium isolates collected from white lupin samples in Egypt were tested with an Egyptian landrace and a French cultivar. The most aggressive isolate was used to screen an additional 15 Egyptian landraces, two cultivars released in Egypt after selection among landraces, one Polish cultivar, and two French cultivars. The assessment of host response to Fusarium was performed in a field, and under controlled conditions in a greenhouse pot experiment. Most landraces and the two Egyptian cultivars showed better resistance with good accordance between field and pot experiment. This experiment showed that Egyptian genetic resources of white lupin possess partial resistance to Fusarium root rot. Egyptian germplasm may be an alternative genetic source for incorporating partial resistance to Fusarium root rot into the breeding pools. This revised version was published online in July 2006 with corrections to the Cover Date.     

Diversity of white and narrow-leafed lupin genotype adaptive response across climatically-contrasting Italian environments and implications for selection

White lupin (Lupinus albus) and narrow-leafed lupin (L. angustifolius) have special interest as high-protein feed crops but their cultivation is limited by low grain yields. This study aimed to support breeding programs targeting Italy or other climatically variable south-European regions by investigating within-species adaptation patterns across contrasting Italian environments. An additional aim was comparing species for yielding ability. Eight narrow-leafed and six white lupin cultivars featuring different origin, phenological type (Mediterranean in both species; winter in white lupin; spring in narrow-leafed lupin) and plant architecture (determinate or indeterminate in both species; tall or dwarf in white lupin) were evaluated in a Mediterranean and a subcontinental-climate site under autumn and late-winter sowing. Additive main effects and multiplicative interaction was preferable to joint regression for modeling yield responses. In both species, cross-over GE interaction was observed (P < 0.05), autumn-sown Mediterranean and subcontinental environments were the most-contrasting for GE effects, and widely adapted material included cultivars of Mediterranean phenological type with indeterminate growth. Material with determinate growth was not among the best-yielding entries in any environment, whereas a dwarf winter-type white lupin entry was specifically adapted to autumn-sown subcontinental environments. White lupin displayed larger genetic variation than narrow-leafed lupin for phenology and other traits. Relationships of morphophysiological traits with grain yield were environment-specific and were locally high for some white lupin traits (early flowering, long reproductive phase, high aerial biomass, low proportion of pod wall). White lupin exhibited higher yielding ability than narrow-leafed lupin in all environments but the late-winter sown Mediterranean one, when comparing locally top-yielding cultivars.     

Field performance of natural narrow-leafed lupin from the northwestern Spain

Summary Narrow-leafed lupin or lupine (Lupinus angustifolius L.) is one of the three species of the genus Lupinus that grows naturally in Galicia (northwestern Spain). In this region, with more than one million of cattle heads, almost 20% of Spanish total, there is no cultivation of any protein legume for feed. Lupins are widely used as a source of protein and energy in livestock feed and would contribute to the supply of vegetable protein at low cost. A 2-year study of natural narrow-leafed lupin germplasm was conducted under winter Mediterranean conditions in northwestern Spain. Fifty-nine wild populations and two cultivars developed in Poland were evaluated for major morphological, phenological, and agronomical characteristics. The objectives were to assess the agronomic potential of this germplasm for the future production and breeding, and to know the relationships among populations studied. Lupin populations showed significant differences for most of the traits studied. Genotype × environment interaction was significant for plant height, green and dry mass, pod length, seeds per pod, seed length and width, and water permeability of seed coat, indicating that some genotypes were better fitted to a specific environment than others. Three narrow-leafed lupin populations (LUP-0098, LUP-0138 and LUP-0200) were identified with suitable agronomical characteristics for their possible future cultivation in the region and breeding purposes. The accession LUP-0138 presented the best behaviour for seed production. These results open the way for the winter narrow-leafed lupin to become a promising crop in the future for the northwestern Spain.     

Effect of the gene for double pod in chickpea on yield, yield components and stability of yield

Five pairs of near isogenic lines (NILs) for the gene for single vs. double pod were used to study the effect of this character on yield and its components (seeds per plant, yield per plant and seed weight). The NILs were sown in 2 years at five locations in ihe first year and four locations in the second. Combined analysis of variance was applied to t he data and no significant differences between isolines were found, but there were significant genotype– location interaction effects for yield and seeds per plant. For both characters the double–podded lines were more stable than the single–podded lines. Although there were significant differences between the five genotypes lor yield per planl and seed weight, the differentes between single– and double–podded lines were almost nil. The results indicate that the double–pod gene has a positive effect on the stability of yield and is not linked to any other gene responsible Tor seed size in chickpea     

Strong heritability across years and sites for pod wall proportion and specific weight in Lupinus albus and genotypic correlation with other pod and seed attributes

Thinner pod walls might contribute to increased yield potential and adaptation of lupins. Fourteen autumn‐sown genotypes of Lupinus albus L. were evaluated over 2 years at four sites in southern Chile. Pod wall proportion (PWP), pod wall specific weight (WSW) and five other pod‐related characters were measured to estimate their genetic variation, heritability across years and sites, and genotypic and phenotypic correlations among the characters. Ranges for PWP and pod WSW were 22.9−43.1% and 16.4−37.4 mg/cm², respectively. PWP in cultivated L. albus was similar to that reported in L. angustifolius; however, specific weight was substantially lower. Highly significant genotypic effects were found for both characters. Broad sense heritabilities were high for PWP (0.63) and moderate for pod WSW (0.46). These characters were significantly correlated, more so genotypically (r_g = 0.67) than phenotypically (r_ph = 0.36). Selection for low PWP should lead to lower pod wall thickness or density, both of which contribute to pod WSW. Nevertheless, selection for pod WSW could achieve further reductions, particularly if practised among low PWP materials.     

Genetic variability and interrelationships of seed yield and yield components in switchgrass

Information on the genetic variability of seed yield and yield components is limited and no information is available on correlations among seed yield and yield components and direct and indirect effects of the yield components on seed yield in switchgrass, Panicum virgatum L. Accordingly, we conducted replicated experiments at Chickasha and Perkins, OK, in 1998 involving 11 lowland type switchgrass populations to assess genetic variation for seed yield and yield components, quantify interrelationships among them, and determine direct and indirect effects of yield components on seed yield through path coefficient analysis to identify traits for indirect selection of seed yield. Significant (P ≤ 0.01) variation existed among the 11 populations over locations for percent seed set and 100-seed weight. Seed yield/plant and the seed yield components panicle number/plant, spikelet number/panicle, and seed number/panicle had significant (P ≤ 0.05) population × location interactions, indicating substantial environmental influence on these traits for these populations. Accordingly, data for these traits were analyzed separately for each location revealing significant (P ≤ 0.01) differences among populations at both locations for each of these traits. Phenotypic correlation between seed yield/plant and seed number/panicle was positive (r = 0.76** at Chickasha and r = 0.72** at Perkins). Path coefficient analyses revealed that seed number/panicle had the highest positive direct effect on seed yield at both locations. Ample genetic variability was present among the switchgrass populations studied to allow breeding improvement of seed yield. Selection for increased seed number/panicle would be the most effective means of indirectly selecting for higher seed yield within this germplasm. Correlation and path coefficient analyses among biomass yield, seed yield, and harvest index indicated that, at least within the switchgrass germplasm studied, it would be possible to breed switchgrass cultivars with enhanced biomass yielding ability and sufficient seed production capability for their commercial propagation.     

A linkage group for genes governing pod characters in peanut

Summary Inheritance and linkage relationships were studied for six morphological characters in a cross between Arachis monticola Krap. et Rig. and A. hypogaea L. All the characters were found to be governed by single dominant genes. The genes governing leaflet krinkling and peg pigmentation assorted independently while the genes for four pod characters viz. catenate nature, beak, reticulation and thin pericarp showed linkage. A linkage map for these genes was proposed.     

Inheritance of pod cross-section in beans (Phaseolus vulgaris L.)

Summary OSU 5062, a green bean line with a tendency for pods to become creasebacked (wider than deep) in cross-section, was crossed to near-round-podded cultivars Oregon 83 and Slenderette, oval-podded Bountiful, and flat-podded Roma, to further clarify the inheritance of pod cross-section. Differences among generations in pod cross-section index (PCS), calculated as pod width/depth, were small in the near-round x creaseback crosses (1.07 and 1.01 for Oregon 83 and Slenderette versus 1.20 for OSU 5062). Bountiful (0.63) and Roma (0.50) differed to a greater extent from 5062. Generation means of individual plant PCS of the F₁ and F₂ were almost identical, were almost exactly intermediate between parents, and strongly supported additive inheritance. Backcross data generally supported additive inheritance, but in some cases indicated degrees of dominance of higher PCS. A generation means analysis indicated additive gene action, but deviations from an additive-dominance model were significant in each cross.     

Seed coat permeability and its inheritance in a forage lupin (Lupinus hispanicus)

Summary The species Lupinus hispanicus, throught its use as self-seeding forage, can contribute to solve the problem of forage scarcity during the summer in the livestock farming of the central-west Iberian Peninsula. A feature of the highest importance in achieving self-seeding is the seed-coat permeability. An evaluation of this characteristic has been carried out in a Lupinus hispanicus collection from Salamanca (Spain), its inheritance, and the influence of daily temperature fluctuations on the softening of the seeds. All the lines but one had impermeable seeds. It was established that the permeability of the seeds is controlled by the genotype of the mother-plant and the inheritance of this characteristic follows a simple Mendelian model, the permeability being recessive. It was also observed that seeds subjected to daily temperature fluctuations had an increased level of permeability.     

Construction of integrated linkage map of a recombinant inbred line population of white lupin (Lupinus albus L.)

We report the development of a Diversity Arrays Technology (DArT) marker panel and its utilisation in the development of an integrated genetic linkage map of white lupin (Lupinus albus L.) using an F₈ recombinant inbred line population derived from Kiev Mutant/{"type":"entrez-protein","attrs":{"text":"P27174","term_id":"14195583","term_text":"P27174"}}P27174. One hundred and thirty-six DArT markers were merged into the first genetic linkage map composed of 220 amplified fragment length polymorphisms (AFLPs) and 105 genic markers. The integrated map consists of 38 linkage groups of 441 markers and spans a total length of 2,169 cM, with an average interval size of 4.6 cM. The DArT markers exhibited good genome coverage and were associated with previously identified genic and AFLP markers linked with quantitative trait loci for anthracnose resistance, flowering time and alkaloid content. The improved genetic linkage map of white lupin will aid in the identification of markers for traits of interest and future syntenic studies.     

Study on the inheritance of potato tuber yield by means of harvest index components and its consequences for choice of parental material

Summary The inheritance of potato tuber yield was studied considering the seasonal course of harvest index. Harvests of several progenies and their parents were performed at intervals and fresh weight of foliage, underground stems, tubers and stolons was assessed.Tuber yield depends on the time of tuber initiation and the proportion of the assimilates allocated to the tubers, as reflected in the increase rate of harvest index. The time of tuber initiation of the progenies was associated with the time of tuber initiation of the earliest tuberizing parent. The mean increase rate of the harvest index of the progenies was in most cases equal to the mean values of parents, however in crosses combining early with late maturing parents the rate equaled the value of the maternal parent. Using these relations, differences in harvest index between progenies can be predicted with a high degree of precision by using the harvest index parameters of the parents. This estimated harvest index showed a fairly good correlation to tuber yield at mid-September and can be used in the prediction of the yield of the progeny. The use of the mid-parent value for this purpose is not suitable.     

Selection for pod retention and pod indehiscence in lentils

Summary The genetic variation for seed yield losses and the response to selection for reduction of such losses was studied by a six-week delay in the timing of harvest in various segregating populations from four lentil crosses. The bulk segregating populations had previously been subjected to different numbers of selection by means of a delayed harvest. The loss in seed yield from a delayed harvest in the two seasons 1981/82 and 1982/83 accounted for 551 and 105 kg/ha seed, representing 34 and 11% of the yield from a correctly timed harvest respectively. Pod drop accounted for 65% of this loss, whereas dehiscence gave 35% of the loss in both seasons. The parents of cross 4 differed significantly for pod dehiscence, with genotype 74TA 550 showing relative indehiscence. Selection by means of a delayed harvest of bulk populations decreased pod dehiscence, mean seed weight and bulk mean yield.     

Genetic analysis of yield and its components in vegetable cowpea (Vigna unguiculata L. Walp)

The F2 and backcrosses of a cross between two vegetable cowpea (Vigna unguiculata L. Walp) varieties with contrasting characteristics were evaluated for pod yield and its components, with the aim of understanding the genetic basis of these characteristics. A four-parameter model incorporating the additive, dominance and additive × additive genetic components fitted the data for pod yield and clusters per plant. The additive and additive × additive effects were positive and were larger than the dominance component. The relatively large additive and the predominantly positive dominant effects suggest that selection would be effective. Pod weight had high broad (84%) and narrow sense heritability (75%) and can be effectively selected for in the early generations. The study suggested that vegetable cowpea improvement programs should focus on selecting for clusters per plant and average pod weight in the early generations, while selection for dry pod yield could be delayed to later generations. It was concluded that pods per plant may be a useful selection criterion in multi-location trials aimed at selecting for stability of yield. This revised version was published online in July 2006 with corrections to the Cover Date.     

The genetic control of highly restricted branching in narrow-leafed lupin (Lupinus angustifolius L.)

Most current cultivars of narrow-leafed lupin have an indeterminate growth habit such that vegetative growth continues while the pods are being filled, causing strong intra-plant competition for assimilates. Restricted-branching (RB) genotypes can reduce this tendency and raise the proportion of the plant's biomass going into grain. Studies on the inheritance of the RB trait showed that two spontaneous mutants, P25598 and P21227, each carried a single incompletely dominant allele conferring the trait, whereas two other spontaneous mutants, P24743 and P25582, and two induced mutants, P26021 and P21238, each carried a single recessive allele conferring the trait. The RB alleles present in P26021 and P21238 seem to be the same, and to be at the same locus as (or tightly linked to) the allele controlling the RB trait in P21227. Similarly, the genes present in P21227 and the induced mutant P25735 appear to be the same when these lines are crossed. However, they do not behave the same in crosses with P26021: thus we propose that there are at least three alleles at the same locus (or at tightly linked loci) that confer RB. Normal-branching plants that are heterozygous at an RB locus generally have fewer leaves on the uppermost branch than homozygous-normal plants. Similarly, RB plants that are heterozygous generally have fewer branchless nodes on the main stem than homozygous-RB plants. The RB trait is associated with a small but significant reduction in the number of leaves on the main stem. However, this relationship is weak and will not prevent plant breeders from selecting both early- and late-flowering RB genotypes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Ontogenetic analysis of yield components and yield stability of durum wheat in water-limited environments

Summary One main reason for the slow improvement of durum wheat in water-limited environments is the lack of clear understanding of the interrelationships among yield components and their compensatory changes under low and erratic moisture availability. Five cultivars, varying in many physiological attributes, were tested under different drought-stress conditions in field and greenhouse experiments. The cause-effect relationships of duration of vegetative period, duration of grain-filling period, number of spikes per m², kernels per spike, kernel weight and grain yield per m² were assessed. Furthermore, yield stability was evaluated. Yield reduction was largest under mid-season stress (58%), followed by terminal stress (30%) and early stress (22%). Cultivar Po was very sensitive to terminal stress.Path-coefficient analysis revealed a complex pattern of relationships among the six variables. An increase in vegetative period reduced the grain-filling period under all conditions. It increased number of kernels per spike under non-stress conditions. The direct effect of spikes per m² on grain yield was significantly positive. However, more spikes per m² resulted in fewer kernels per spike and a low kernel weight and, as a result, a negative relationship with grain yield under early stress. Grain-filling period had a strong influence on grain yield via kernel weight. Kernels per spike had the largest direct effect on grain yield. However, it was negatively correlated with kernel weight, especially under terminal stress. Grain yield heavily depended on kernels per spike under early stress and grain-filling period and kernels per spike under terminal stress.Variation in drought susceptibility index among cultivars was significant under early and terminal stress conditions, but not under mid-stress conditions. Yield potential and stability were not correlated for the different drought-stress conditions.Longer grain-filling period, increased number of kernels per spike and limited spike number per m² can be used as selection criteria for sustainable yield in water-limited environments.     

The inheritance of fruit yield and stolon production in everbearing strawberries

Summary The everbearing progeny from crosses between three short-day and four everbearing genotypes were assessed for early fruit yield and stolon production. General combining ability (GCA) was found to be important for fruit yield but specific combining ability (SCA) was more important for stolon production. The results suggested that it should be possible to combine early fruiting and adequate stolon production in an everbearing genotype. The breeding strategy necessary to achieve this aim is discussed.     

Variation in some yield determining components in muscadine grapes and their correlation to yield

Summary Six Vitis rotundifolia Michx. (muscadine) grape genotypes were measured to determine variation and simple correlations between flower and fruit number/cluster, fruit cluster and individual fruit weight, fruit set and total vine yield. Significant variation was found for each trait, except fruit cluster weight. Range in mean values across selections for each trait were: 72 to 202 flowers/cluster; 16 to 26 fruit/cluster; 88.1 to 112.2 g/fruit cluster; 3.4 to 7.2 g/fruit; 11.3 to 23.4% fruit set; and 21.0 to 71.0 kg/vine for yield. Simple correlation values ranged from r=0.05 for flower number to cluster number to r=0.69 for fruit number to cluster weight. No trait was highly correlated to total yield. Therefore, to increase yield in muscadines it appears best to select for total yield and not for components contributing to yield.Paper No. 10968 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC 27695-7601.